title: Antimyeloperoxidase antibodies are a useful marker of disease activity in antineutrophil cytoplasmic antibody-associated vasculitides.
abstract: OBJECTIVE
  To evaluate the relevance of monitoring antimyeloperoxidase antibody levels in the management of antimyeloperoxidase-associated vasculitides.
  
  
  METHODS
  Thirty-eight patients with antimyeloperoxidase-associated vasculitides were included: microscopic polyangiitis (n = 18), Wegener's granulomatosis (n = 15) and Churg-Strauss syndrome (n = 5). Baseline characteristics and outcomes were recorded. Serial measurements of antimyeloperoxidase antibody levels were performed (ELISA, positive > or = 20 IU/ml).
  
  
  RESULTS
  All patients achieved vasculitis remission after a mean time of 2.0 months (SD 0.9), with a significant decrease in the mean antimyeloperoxidase antibody level at remission (478 vs 41 IU/ml (SD 598 vs 100); p<0.001). Twenty-eight (74%) patients became antimyeloperoxidase antibody negative. After a mean follow-up of 54 months (SD 38), 12 cases of clinical relapse occurred in 11/38 (29%) patients. Relapses were associated with an increase in antimyeloperoxidase antibody levels in 10/11 (91%) patients (34 vs 199 IU/ml (88 vs 314); p = 0.002). The reappearance of antimyeloperoxidase antibodies after achieving negative levels was significantly associated with relapse (odds ratio 117; 95% CI 9.4 to 1450; p<0.001). Antimyeloperoxidase antibodies showed a positive predictive value of 90% and a negative predictive value of 94% for relapse of vasculitis. Up to 60% of cases of relapse occurred less than 12 months after the reappearance of antimyeloperoxidase antibodies. Relapse-free survival was significantly worse for patients who exhibited a reappearance of antimyeloperoxidase antibodies than in those with persistent negative antimyeloperoxidase antibodies (p<0.001). The antimyeloperoxidase antibodies serum level was strongly correlated with the Birmingham vasculitis activity score and the disease extent index (r = +0.49; p = 0.002).
  
  
  CONCLUSIONS
  Through monitoring, antimyeloperoxidase antibodies are a useful marker of disease activity and a good predictor of relapse in antimyeloperoxidase-associated vasculitides.
authors.affiliation: Department of Internal Medicine, Groupe Hospitalier Pitié-Salpétrière, 47 boulevard de l'Hôpital, 75013 Paris, France.
authors.forename: B
authors.initials: B
authors.lastname: Terrier
authors.forename: D
authors.initials: D
authors.lastname: Saadoun
authors.forename: D
authors.initials: D
authors.lastname: Sène
authors.forename: P
authors.initials: P
authors.lastname: Ghillani
authors.forename: Z
authors.initials: Z
authors.lastname: Amoura
authors.forename: G
authors.initials: G
authors.lastname: Deray
authors.forename: B
authors.initials: B
authors.lastname: Fautrel
authors.forename: J-C
authors.initials: JC
authors.lastname: Piette
authors.forename: P
authors.initials: P
authors.lastname: Cacoub
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood*; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009195:Peroxidase / Q000276:immunology*; D011379:Prognosis; D012008:Recurrence; D012074:Remission Induction; D014657:Vasculitis / Q000175:diagnosis* / Q000188:drug therapy; D055815:Young Adult
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D001323:Autoantibodies; D015415:Biomarkers; D009195:Peroxidase